I just replaced my alternator and serpentine belt and I am now having problems with the AC.

When I am driving and accelerating the AC works and blows cold air, but when I stop at a light, the air gets hot and the car will kind of rumble every 10 secs or so. It does not do this when the AC is off.

Please help!

 

When you turn on the AC is the cooling fan / s blowing? Sounds like the fans are not turning.

 

I don't think so.

 

Could be low on freon....just a coincidence that it happened after the other work. The rumble sounds like the compressor starting and stopping due to low freon.

Open the hood and watch the compressor clutch while the car idles and the A/C is on cold. The clutch may cycle engaged and not, but it should not do it very often...

 

it sounds like the fan is blowing. i checked the freon and it is good.

I just got home from work and while sitting in the driveway in park, it was blowing cold air and no rumble to it.

Where is the compressor clutch located?

 

How did you check the freon? That normally requires a set of gauges for the A/C.
The air conditioner clutch is located on the front of the compressor. When the A/C is off, or has reached the set temp from the inside selection, the clutch face will not spin with the pulley which is between the clutch and compressor. It also has a low freon switch which shuts off the system if to low. It also disconnects the compressor clutch when you go wide open throttle.

 

When I initially thought it was freon I purchased the 134A freon with a gauge from Autozone.

I'll check the clutch when I get home from work. Thanks.

 

IMG_0902.MOV

 

Here is the link for the video of my car with the AC running. The car rumbles when it spins.

 

I would try spraying the clutch area with some WD40. It is a cleaning agent and may quiet it down a bit. Sounds like maybe the clutch is going out. Could also be a bad bearing in the compressor.

When it cycled on, was that you switching it off and on or was that the car? If that was doing it by its self, it could be a switching issue. Since you say it is full of freon, the low pressure switch may be bad. When set to full cold in warm weather, the clutch should remain engaged nearly all the time.

 

It was the car switching it on and off. I had the air on and to the max. I'll try some wd40 see if that helps at all.

Thank you so much for your input and expertise.

 

Based on your last post, either the system is low on freon, the clutch is bad, the low pressure switch is bad. The reason the clutch is engaging on and off is the system is reading a low pressure and does that to keep from damaging things. It is a possibility of an over charge but seems doubtful.

I would suggest you have the system emptied, evacuated, and refilled. At that point, the shop will check for leaks and advise you on the problem.